Community Forums

Gary RVRoamer · 05-24-2014, 02:30 PM

Put me in the 62-64 crowd, with my ISL in sixth gear at about 1650 RPMs. That's the most consistent for turnpike cruising, around 8.1 mpg. I've occasionally done as well well in the high 50's on an empty two-lane, but usually that dips lower.

iamblum · 09-06-2014, 10:09 AM

On my way to Oregon from utah I got a little over 7 with my 454 hauling butt, on my way back I went slow kept it between 60 and 65 for the most and hit just under 9

Don and Dale · 09-06-2014, 10:22 AM

Coming back from central Oregon last week, we averaged 9.3 mpg at 62 - 65 mph. Highest price we saw for unleaded was $4.89 in Needles, Ca., but we didn't buy there because of that price.
We don't have a toad, however. Love that V10 with the 5 star tune.

mgscott4 · 09-06-2014, 08:00 PM

Natchez Trace Parkway, 445 miles, speed limit 50 mph, no stop signs or lights. 2 lane scenic drive.

I normally get 8.0 mpg. I got 9.8 on the parkway. I turned OD off, I stayed in 5th gear and around 1800 - 1900 RPM.

JFXG · 09-07-2014, 09:04 PM

Quote:

Originally Posted by TimLoon

........ What was really surprising was that when I drafted tractor trailers at what I felt was a safe distance at the legal speed of 65, I actually picked up 2 mpg ......

Back in the '70s I spent some years traveling by motorcycle-- two wheel fulltiming, you might say. Six times across the country.

Anyway, I discovered there's a drafting sweet spot with big trucks that is dangerous as all hell, but can really save you gas. (This is really tough in anything other than really sparse traffic) I would find an 18 wheeler and move up next to him, just at or slightly forward of his trailer wheels. Then edge over until you're just about 4 feet from the wheels and you enter a wind vortex that will carry you along with no effort at all. I'm not kidding, I've put my bike in neutral and been carried along by the truck at 70mph. Needless to say, high-risk research! ;-)

Mr_D · 09-07-2014, 09:13 PM

According to Cummins the sweet spot is about 200 rpm over max torque RPM, which would be 1600 rpm, giving me 1050 ft lbs. However we have the Banks kit so now I have 1200 ft lbs from 1400 to past 1700 RPM.
Over 40,000 miles I've averaged 7.06 mpg, I figure 7 and that's about right. On the flats I will see over 13 mpg on my VMSpc and as low as 3 mpg in the Columbia Gorge at 70 mph fighting a very heavy headwind! Downhill I've seen 254 mpg.

CampingCajun · 09-08-2014, 08:50 AM

Running at 1500 rpm which is about 66 - 67 mph get 8.0 mpg. ISC 360.

Gordon Dewald · 09-08-2014, 08:55 AM

9.6 running at 62 in cruise. ISL 450. Without trailer.

dunk05 · 09-11-2014, 02:46 PM

Just finished a 5000 mile trip to South Dakota, MN, IL, IN, PA, NC, TN, AR OK, TX, and back home. Towing a Ford Focus on tow dolly. Different kinds of roads light to heavy traffic, lots of wind and rain. Averaged 9mpg. 2007 Lexington Ford E450. I drive like someone else said Like an egg under gas pedal. I drive around 60-65. Have a speed controller sitting to my right.

MartinP · 09-13-2014, 08:16 AM

Some folks may find this hard to believe but, just got back from a 1500 mile run up to Oregon. Ran at 65 most of the way up as I had an appointment. On the way home ran 60 on the flat. Checked the numbers several times and it appears the MH got around 14 MPG. I have changed the gearing in the back axle.

Martin

Bumps · 09-13-2014, 08:41 AM

Quote:

Put me in the 62-64 crowd, with my ISL in sixth gear at about 1650 RPMs. That's the most consistent for turnpike cruising, around 8.1 mpg....

My "sweet spot" is about 62. Am seeing the similar results as Gary_RVRoamer. And I never have to worry about passing anybody 'cause they are all passing me!

\ken

chawkins99 · 09-13-2014, 01:22 PM

When I first got my coach, I kept detailed records for the first few months and got between 8 & 9 MPG. I then got a ScangaugeD and that showed roughly the same, so I quit keeping records and now rely on my Scangauge.
I really LOVE the readout when I'm going downhill

Not so much uphill

I normally run 60-65mpg which is around 1600RPM. My coach will move to top gear at around 45mph.

ElvistheKing · 09-13-2014, 01:57 PM

I always wonder when people are working out the most economical speed to drive out, what price they put on their time?

GA Navigator · 09-13-2014, 11:13 PM

Quote:

Originally Posted by ElvistheKing

I always wonder when people are working out the most economical speed to drive out, what price they put on their time?

Some folks might enjoy the time behind the wheel so the speed that gives max endurance might be appropriate for them.
Personally, I care about my costs, but I'm not going stress too much over maybe 1 mpg. I try to save on where I buy fuel. Many times fuel is 25 cents cheaper 15 miles from the interstate hwy.

1994 Holiday Rambler Navigator
Cummins 8.3
Allison MD3060